SN2 Fluorination reactions in ionic liquids: a mechanistic study towards solvent engineering

Authors:
Publisher website
Google Scholar
Abstract
In the catalysis of SN2 fluorination reactions, the ionic liquid anion plays a key role as a Lewis base by binding to the counterion Cs+ and thereby reducing the retarding Coulombic influence of Cs+ on the nucleophile F−. The reaction rates also depend critically on the structures of ionic liquid cation, for example, n-butyl imidazolium gives no SN2 products, whereas n-butylmethyl imidazolium works well. The origin of the observed phenomenal synergetic effects by the ionic liquid [mim-tOH][OMs], in which t-butanol is bonded covalently to the cation [mim], is that the t-butanol moiety binds to the leaving group of the substrate, moderating the retarding interactions between the acidic hydrogen and F−. This work is a significant step toward designing and engineering solvents for promoting specific chemical reactions.

This publication has 37 references indexed in Scilit: